Quality of service (QoS) provides access network operators and service operators with a set of tools to enable service and subscriber differentiation. Such tools are becoming increasingly important as operators are moving from a single to a multi-service offering at the same time as both the number of mobile broadband subscribers and the traffic volume per subscriber is rapidly increasing.
Bearer is the enabler for traffic separation, it provides differential treatment for traffic with differing QoS requirements. The bearer is the level of granularity for bearer-level QoS control. That is, all packet flows mapped to the same bearer receive the same packet-forwarding treatment. The packet-forwarding treatment comprises, for example, scheduling policy and queue management policy. Providing different packet-forwarding treatment requires separate bearers. QoS is class-based, where each bearer is assigned one and only one QoS class identifier (QCI) by the network. The QCI is a scalar that is used within the access network as a reference to node-specific parameters that control packet forwarding treatment.